ScholarWorks@숙명여자대학교

초록

We investigated the characteristics of blue and white inverted organic light-emitting diodes (IOLEDs) varying indium tin oxide (ITO) thicknesses. We measured the optical transmittance, reflectance, sheet resistance, and surface roughness of ITO films with different thicknesses and performed optical simulations to calculate external quantum efficiencies (EQEs) for the devices. The simulation results indicate that the effect of ITO thickness on device efficiency decreases as the number of emission colors increases. We fabricated blue, 2- and 3-wavelength white IOLEDs. The blue IOLEDs with 70 nm ITO showed a 13% higher EQE compared to that of the device with 150 nm ITO. However, the devices with 70 nm ITO exhibited 6% and 1% higher EQEs compared to those of the device with 150 nm ITO in the 2- and 3-wavelength white IOLEDs, respectively, suggesting that the effect of ITO thickness on the EQE of white IOLEDs is weaker than in single-color IOLEDs.

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